Autoimmune conditions are characterized by the body attacking itself by mounting an immune response against itself. Various antigens often with defined epitopes recognized for some HLA genotypes, have been identified, including those associated with insulin dependent diabetes mellitis (IDDM), rheumatoid arthritis (RA) [e.g., collagen type II 390–402 IAGFKGEQGPKGE (SEQ ID NO:1), systemic lupus erythematousis (SLE), ankyosing spondylitis (AS), pemphius vulgaris (PV) [epidermal cell adhesion molecule desmoglein 190–204], multiple sclerosis (MS), Myelinproteolipid MPL [peptide sequence KNIVTPRT (SEQ ID NO:2], certain types of psoriasis, and uveoretintis (J. Hammer et al 1997, Adv. Immunol, 66:67; R. Tisch, et al, 1999, J. Immunol. 163:1178; J. Yoon, et al, 1999, Science 284:1183; P. J. Ruiz et al, 1999, J. Immunol., 162:3336; C. J. Krco, et al, 1999, J. Immunol. 163:1661). In other cases, peptides are known that induce in animals, a condition similar to ones found in humans, such as GDKVSFFCKNKEKKC (SEQ ID NO:3) for antiphospholipid antibodies associated with thrombosis (A. Gharavi et al, 1999, J. Immunol., 163:2922) or Myelin peptides for experimental autoimmune encephalitis as a model for MS (P. J. Ruiz, et al, 1999, J. Immunol., 162:3336; S. Araga, et al, 1999, J. Immunol., 163:476–482; N. Karin, et al, 1999, J. Immunol., 160:5188; L. M. Howard, et al, 1999, J. Clin. Invest., 103:281). Glutamic acid decarboxylase and specific peptides have been identified for IDDM (R. Tisch, et al, 1999, J. Immunol., 163:1178; J. Yoon, et al, 1999, Science, 284:1183). Many of these conditions are also characterized by elevated levels of one or more different cytokines and other effectors such as TNF (S. Kleinau, et al, 1999, J. Immunol. 162:4266; T. Preckel, et al, 1998, Eur. J. Immunol., 28:3706; P. Wooley, et al, 1992, J. Immunol., 151:6602) as well as autoantibodies, including in some cases, anti-costimulator molecules, in particular, those for CTLA-4 (CD152) on CD4+ cells (T. Matsui, et al, 1999, J. Immunol., 162:4328).
Efforts are underway to attack cells or cellular products of the immune system and thereby treat autoimmune conditions, allergies, asthma and tranplantation rejection using as reagents presumptive antigenic peptides or proteins, peptides representing certain T cells, monoclonal antibodies, recombinant proteins binding various effector cells or molecules such as TNF and IgE.
The following immunomodulatory approach contrasts with the mode of action for products which are antigen specific.
A fusion protein LFA-3TIP (Amevive™ from Biogen), purportedly a molecule composed of the first extracellular domain of LFA-3 fused to the hinge (CH2 and CH3 domains of human IgG1) which targets the CD2 receptor on T cells, is being evaluated for psoriasis and for xeno- and allograft rejection. LFA-3TIP is bifunctional (i.e., two identical LFA-3 regionsand TIP) and, therefore is a complex conjugate molecule. According to Biogen, LFA-3TIP is a recombinant fusion protein designed to modulate immune response by blocking the cellular pathway that activates T cells. It is presumed by the present inventor that the compound is acting on a subset of memory effector cells with a down modulation or re-direction of modulation activity.
These less antigen specific approaches also utilize monoclonal antibodies that act on activated T cells and down regulate them such as by anti-CD3 (Protein Design Laboratories) or block APC and T cell interaction by anti-ICAM-3 (ICOS). MEDI-507 (Medimmune) is believed to be a humanized monoclonal antibody, for psoriasis that also targets CD2, presumably for removing or inactivating those cell types. Other diseases, such as, tissue transplantation rejection and allergies are also being tested by this approach. In contrast to acting on cell surface markers, rhu-Mab-E25 (Genentech) is believed to be a humanized monoclonal antibody against IgE that binds to circulating IgE, with the goal of preventing activation of mast cells. In contrast, other researchers are developing monoclonal antibodies to act on symptoms or agents directly causing disease symptoms. Remicade Infliximab (Centocor) is purported to be a monoclonal antibody to TNF. Anti CD40 ligand has been used for treatment in animal model of MS (L. M. Howard, et al., 1999, J. Clin. Invest, 103:281). A recombinant generated designed protein Enbrel (Immunex) is purported to comprise two molecules of r-DNA derived TNF receptor, and is intended to block TNF's action.
It should be noted, however, that many of these agents are not sufficiently disease specific and often recognize and could affect normal cellular and body constituents that have a defined and necessary role in normal immune defenses which are still needed.
More antigen or disease specific approaches are exemplified by the attempt to treat MS patients by oral administration of myelin proteins which have recently been reported; the same group of searchers are also using collagen type II for treatment of patients with rheumatoid arthritis. These treatments are designed to attack at the level of the gut associated lymphoid tissues (GALT) to induce tolerance by antigen specific suppression of the immune system. It is not known if these treatments use the intact protein or a hydrolyzate containing smaller peptides. See D. Hafler, et al, 1988, J. Immunol., 141:181; K. Wucherpfennig, et al, 1990, Science, 248:1016; K. Ota, et al., 1990, Nature, 346;183; and H. Weiner, 1999, PNAS, 88:9161.
Several researchers are testing peptide based materials for treatment of autoimmune conditions. One approach uses peptide as immunogen, given orally in large quantities. The peptide represents a peptide sequence that is thought to be the autoimmune epitope itself or a modified form which may also have altered binding or improved stability properties. By use of the peptide it is thought that either the normal peptide or an altered peptide ligand (APL) will bind to the T cell receptor (TCR) and induce a state of anergy since the multiple sets of bindings that would occur with antigen presentation with an antigen presenting cell (APC) do not occur (A. Faith, et al., 1999, J. Immunol., 162:1836; Soares, et al, 1998, J. Immunol., 160:4768; M. Croft, et al, 1997, J. Immunol., 159:3257: L. Ding, et al., 1998, J. Immunol., 161:6614; and S. Hin, et al, 1999, J. Immunol., 163:2363). Some of the approaches with APL include using related amino acids such a D amino acids (U. Koch, et al, 1998, J. Immunol., 161:421), amino acids with substituted side chains (R. De Palma, et al, 1999, J. Immunol., 162:1982), methylene groups to replace peptide bonds in the peptide backbone (L. Meda, et al, 1996, J. Immunol., 157:1213) and N-hydroxyl peptides (S. Hin et al, J. Immunol., 163:2363). Several groups have studied the effect of various substitutions of side chains and the MHC and TCR molecules (L. Raddrizani, et al, 1997, J. Immunol., 159:702; T. M. Clay, et al, 1999, J. Immunol., 162:1749; L. Radrizanni, et al., Eur. J. Immunol., 1999, 29:660). With insulin activity it has been shown that a one amino acid change on the β- chain can abolish its oral immune tolerance activity in two (2) mechanistically different IDDM murine models (D. Homann, et al, 1999, J. Immunol., 163:1833). While not an autoimmune epitope it has been reported that a single change from threonine to alanine can abolish biological activity (C. L. Sutherland, et al, 1999, J. Immunol., 162:4720); a switch from phenylalanine to alanine alters the bee venom phospholipase to an inactive form (A. Faith, et al, 1999, J. Immunol, 162:1836); as does a switch from tyrosine to alanine change from active to inactive for another system (S. Hausman, et al, 1999, J. Immunol., 162:5389).
In another approach based on peptide materials, truncated peptides of autoimmune inducing epitope are used as antagonist in an animal model to treat the particular condition (N. Karin, et al, 1999, J. Immunol., 160:5188). Several groups are using synthetic amino acid polymers that are considered to represent epitopes which contain Tyrosine (Y), Glutamic acid (E), alanine (A) and lysine (K) to target T cells such as Copolymer 1. In one study Copaxone is being used as an oral tolerance delivery approach to treat MS patients. Copaxone is believed to be a synthetic copolymer of four amino acids (D. Hafler, et al, 1988, J. Immunol., 141:131). Modified peptides of peptide epitopes are reportedly being studies for treatment of various autoimmune conditions, including MS and PV (desmoglein-3) (J. Hammer, et al, 1997, Adv. Immunol., 66:67; K. Wucherpfennig, et al, 1995, PNAS, 92:11935). The scientists doing these studies may also be using Myelin proteolipid associated peptide epitope, a polymer or derivative of this epitope for MS, (Wucherpfennig, et al, Id.).
Peptides that are unique to the T cell antigen receptor molecule are found in a particular part of the variable region, usually the third hypervariable region of the beta chain of the T cell antigen Receptor (TCRβVX) (B. Kotzin, et al, 1991, PNAS, 88:9161; J. Oksenberg, et al, 1990, Nature, 345:344; S. Zamil, et al, 1986, Nature, 324:258). One such peptide is apparently being evaluated for a psoriasis vaccine as IR 502 and others for rheumatoid arthritis (D. P. Gold, et al, 1997, J. Neuroimmunology, 76:29). In this case an immune response to the TCRβV3 (C. L. Sutherland, et al, 1999, J. Immunol., 162:4720) peptide is generated with the goal to have the body eliminate the particular T cells and by so removing the T cells responsible for the condition, treating the condition. However, this approach has the potential of eliminating other T cells that contain the same βV3 peptide sequence besides the one responsible for the autoimnune condition.
Still another peptide approach uses complimentary peptide vaccine that induces T cell anergy and prevents Experimental Autoimmune Encephalitis (EAE) in rats by induction of anti-TCR antibodies (a la anti-idiotype) and thereby elimination of these cells (S. Araga, et al, 1999, J. Immunol., 163:476).
The present inventor has previously discovered and described immunomodulatory peptide constructs which include a first peptide which is an antigenic peptide associated with disease or the causative organism of disease covalently bonded to a second peptide which is a T cell binding ligand. These heterofunctional cellular immunological reagents are described in the commonly assigned U.S. Pat. No. 5,652,342, the disclosure of which is incorporated herein, in its entirety, by reference thereto. According to this patent, representative T cell binding ligands include, for example, portions of MHC Classes I and II, such as, b-2-microglobulin, portions of LFA-3, portions of the Fc region of the heavy chain of immunoglobulins, Ia+ molecules, Among the general disclosure of antigens associated with disease, mention is made of antigens associated with auto-immunity, including diabetes, Rheumatoid arthritis and thyroiditis.